I watched this game. I am only 2.6k MMR myself so no pro at all but some observations I made:
The biggest problems were that your Tidehunter/Tinker top lane got crushed and that you are at the level where nobody knows how to deal with Bloodseeker. You didn't really help much with the first problem in that you left bottom lane for the first time at 19 minutes by which point top was already horribly lost. Lich is not the best support for ganking but he is great at counter-ganks and teamfights especially once you have your ult.
For the period of 13-19 minutes, you didn't really achieve anything at all. At 13 minutes in the game, things are looking great for you. You are lvl 11 which 2-3 levels higher than anyone on the enemy team and Bloodseeker is 8th in the game on net worth and your Sven is 1st. With that kind of advantage, you are the strongest hero on the map and you need to be looking for fights you can take part in. Instead, you spend the next 6 minutes mostly alone in bot lane against Bloodseeker often not even in exp range presumably because you are scared of being ruptured or ganked, in that 6 minutes you manage a grand total of 4 last hits and 1 deny. By 19 minutes, you are still lvl 11 and our now outlevelled by the enemy Death Prophet who is also by far the most farmed hero in the game at that point and is now ready to be a complete PITA to play against. Bloodseeker has recovered to the point where he can start being dangerous. Sniper hasn't been punished for his ridiculous Boots of Travel rush item build and your Tinker is even further behind than he was before.
Following on from that, you didn't buy a single TP scroll all game. That item is what allows you to be in the teamfights as they break out. Also, in this case of this specific match, teleporting back to your fountain allows you to escape Bloodseeker whenever he ruptures you.
While you were in the laning phase, like many new support players, you were way too passive. Lich & Sven should be a far more difficult lane for a solo Bloodseeker than you made it. You barely right-clicked Bloodseeker at all which should be an easy way to harass him given that you are ranged and he is not.
You did not upgrade the courier all game. As a support, that part of your job.
You did not buy wards until 32 minutes into the game and even then, you didn't place them. As a support, that is also part of your job. In comparison, the other team's Rubik warded all game.
Those were the biggest things you did wrong in my view. A few other things I noticed that probably didn't change that game that much but are things you should look out for:
The order you bought your items at the start was a little weird: You bought wand before boots which you should never do unless you are laning againt Bristleback or someone else you expect to be spamming abilities. Also, you kept your brown boots in your stash until you completed your full tranquil boots which almost killed you a couple of times. Remember that you can get brown boots at the side shop.
There was almost 4 minutes between the point where you could afford to complete your mek and you actually having the mek in your inventory during most of which, the courier was unused. It would be useful for you to learn how to use quick buy, that way you get an audio notification whenever you can afford to buy something.
You should be using Sacrifice at lvl 1 even though you will of course be at full mana. It forces the creep wave closer to your tower making it safer for your carry to farm and you also get experience from the creep you sacrifice.
You started the game with 525 gold so I am guessing that you randomed then repicked? Don't do that. Especially when there are only 3 heroes that you have played more than 5 times.
Overall, you were not terrible in the team fights but there were a couple of times where you forgot to use mek and some missed opportunities to ult. Also your first death was avoidable, you and Tide were never going to be able to kill a full health Bloodseeker at this point especially without either of your ultis so running across the river to do it was a little stupid.
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